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Thread: Luxeon III and Luxeon V

  1. #1
    Flashaholic* Nake's Avatar
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    Default Luxeon III and Luxeon V

    Why is the Luxeon III rated at 100K hrs. of life and the Luxeon V at only 1K hrs? These were in a couple of Nuwais I was looking at.

  2. #2
    Flashaholic* Timson's Avatar
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    Default Re: Luxeon III and Luxeon V

    Because the emitter in a Lux III has a single die (light source).

    The LuxV has 4 dies closely bunched together in a tight square.

    This reduces life as it generates a lot more heat in the emitter that one with a single die.

    Heat spells death for LED's.

    1000hrs is still a lot of runtime.

    Unless you're using the light for extremely long extended periods of time (constantly on) you should get a lot more life than that.

    By the time the emitter has given up the ghost it will be totally obscelete anyway and you'll be hankering for something newer and brighter.


    Tim.
    M3-CB, C3-HAIII, A2-RD, Fenix L1P, Fenix P1D-CE, Tri-Star Phaser, Inova T3, Mag85, SNII Clone, DD LuxIII Mag,

    Trilobike
    , Hot-Diver

  3. #3
    Flashaholic* 45/70's Avatar
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    Default Re: Luxeon III and Luxeon V

    Just thought I might add, there really aren't many LEDs (bright ones anyway) that will actually run 100,000 hrs. The only way it could be done is to drive them well below spec and/or in a closely controled enviroment. Hence, why you allways see "up to 100,000 hrs". I think Lumileds specifies 800-1000 hrs for a Luxeon V driven at spec before it's output drops to 50%. I think the same for a Lux III, is something like 6000 hrs, due to there being only one die, as Timson pointed out. Don't quote me on these figures but, they are pretty close.

    Dave

  4. #4
    Flashaholic* chesterqw's Avatar
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    Default Re: Luxeon III and Luxeon V

    what timson said is correct.

    the luxeon V has four luxeon I's die and so the heat created in such a small package will be ALOT more then 1 die itself.

    the heat will cause the phosphor to degrade faster and thus emit less light.

    unlike what 45/70 said, the luxeon I III and K2 has more then 6000hrs.

    the 3 luxeons above if driven at spec, will have at least 60% of the total lumen after 50K hours. and 70% left for K2.

    the luxeon V colour led has a longer life, as there is no phosphor there to degrade but they still have a short life compared to the luxeon I,III and K2.



    that is why the luxeon V white LED has a very short life.
    if killing was legal, i would have killed countless number of people...

  5. #5
    Flashaholic* 45/70's Avatar
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    Default Re: Luxeon III and Luxeon V

    I stand corrected chesterqw! Possibly I'm thinking of overdriven applications.

    Dave

  6. #6
    Flashaholic* Nake's Avatar
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    Default Re: Luxeon III and Luxeon V

    Thanks guys. So much to learn and so little time.

  7. #7
    *Retired* NewBie's Avatar
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    Default Re: Luxeon III and Luxeon V

    For the Philips LumiLEDs Luxeon III:

    Average Lumen Maintenance Characteristics
    Lifetime for solidstate lighting devices (LEDs) is typically defined in terms of lumen maintenancethe percentage of initial light output remaining after a specified period of time. Lumileds projects that white, green, cyan, blue, and royal blue LUXEON III products will deliver, on average, 70% lumen maintenance at 50,000 hours of operation at a 700 mA forward current or 50% lumen maintenance at 20,000 hours of operation at a 1000 mA forward current.

    This performance is based on independent test data, Lumileds historical data from tests run on similar material systems, and internal LUXEON reliability testing. This projection is based on constant current operation with junction temperature maintained at or below 90C. Observation of design limits included in this data sheet is required in order to achieve this projected lumen maintenance.
    Page 15:
    http://www.lumileds.com/pdfs/DS45.pdf


    Philips Luxeon V:

    Average Lumen Maintenance Characteristics

    Heat Sink Temperature Drive Current Average Lumen Maintenance After 500 Hours of Operation
    35C 700 mA 90%
    75C 700 mA 75%
    85C 600 mA 65%
    Notes for Table 8:
    1. LUXEON V Portable is designed primarily for portable lighting and other applications requiring operating lifetimes of 500 hours and less. While the device will operate past 500 hours, its lumen maintenance cannot yet be characterized.
    Longer life versions of white LUXEON V will become available in the future. (we are waiting...)
    2. Average lumen maintenance is dependant on heatsink temperature. A recoverable light output loss may occur during the first 500 hours of operation.
    Page 9:
    http://www.lumileds.com/pdfs/DS40.pdf


    Philips Luxeon I:

    Average Lumen Maintenance Characteristics
    Lifetime for solid-state lighting devices (LEDs) is typically defined in terms of lumen maintenance—the percentage of initial light output remaining after a specified period of time. Lumileds projects that LUXEON products will deliver on average 70% lumen maintenance at 50,000 hours of operation. This performance is based on independent test data, Lumileds historical data from tests run on similar material systems, and internal LUXEON reliability testing. This projection is based on constant current 350 mA operation with junction temperature maintained at or below 90C. Observation of design limits included in this data sheet is required in order to achieve this projected lumen maintenance.
    Page 16:
    http://www.lumileds.com/pdfs/DS25.pdf


    Philips Luxeon K2:

    Average Lumen Maintenance Characteristics
    Lifetime for solidstate lighting devices (LEDs) is typically defined in terms of lumen maintenance—the percentage of initial light output remaining after a specified period of time. Philips Lumileds projects that white LUXEON K2 products will deliver, on average, 70% lumen maintenance at 50,000 hours of operation at a forward current of 1000 mA. This projection is based on constant current operation with junction temperature maintained at or below 120C. Philips Lumileds projects that green, blue, cyan and royal blue LUXEON K2 products will deliver, on average, 70% lumen maintenance at 50,000 hours of operation at a forward current of 1000 mA. This projection is based on constant current operation with junction temperature maintained at or below 150C. Philips Lumileds projects that red, red-orange and amber LUXEON K2 products will deliver, on average, 70% lumen maintenance at 50,000 hours of operation at a forward current of 350 mA. This projection is based on constant current operation with junction temperature maintained at or below 120C.
    This performance is based on independent test data, Philips Lumileds historical data from tests run on similar material systems, and internal LUXEON reliability testing. Observation of design limits included in this data sheet is required in order to achieve this projected lumen maintenance.
    Page 3
    http://www.lumileds.com/pdfs/DS51.pdf


    What is junction temperature? It is the temperature of the little die inside, at the the heart of the LED. It is the part that actually produces light. One can roughly estimate this by using the LEDs C/W rating on the datasheet, calculating the power consumed by multiplying the forward voltage times the current, then multiplying this times the C/W. Then one measures the slug temperature (the mounting slug or thermal slug of the LED), and adds this to the die temp from the previous step. Then you have die temperature.

    Notice how in the K2 statement above, the green, blue, cyan and royal blue and white(phosphor) parts all have the same estimated life. Key to note is on the white parts, how the die must stay below 120C to hit that lifetime. This is quite different than the 185C that was advertised back when the part was officially announced in February 2005, and they were talking about just mounting them to a board, no heatsinking was necessary at lower currents....
    Last edited by NewBie; 11-05-2006 at 12:11 PM.

  8. #8
    Flashaholic* Long John's Avatar
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    Default Re: Luxeon III and Luxeon V

    NewBie

    Best regards

    ____
    Tom
    It's cheaper to get a high quality light than spending money for many cheap lights.

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